Methods and systems for a vehicle air conditioning system

Abstract

Methods and systems are provided for an air conditioning system. An example method of determining current through a compressor suction valve in a vehicle air conditioning (AC) system is provided, the AC system comprises an evaporator fan and the method includes determining the speed of the evaporator fan and determining the current through the suction valve based on the speed of the evaporator fan.

The invention claimed is: 
     
       1. A method comprising:
 determining a speed of an evaporator fan; 
 determining a current through a compressor suction valve in an air conditioning (AC) system based on the speed of the evaporator fan. 
 
     
     
       2. The method of  claim 1 , wherein determining the current through the suction valve comprises:
 determining a relationship between current through the suction valve and at least one of a temperature of air entering the evaporator fan and a target temperature of the evaporator fan. 
 
     
     
       3. The method of  claim 2 , wherein air entering the evaporator fan is taken from outside of a vehicle comprising the AC system, and wherein determining the temperature of air entering the evaporator fan comprises modifying a measured temperature of air outside of the vehicle based on a speed of the vehicle. 
     
     
       4. The method of  claim 3 , wherein determining the current through the suction valve further comprises determining a relationship between current through the suction valve and at least one of the modified measured temperature of air outside of the vehicle and the target temperature of the evaporator fan. 
     
     
       5. The method of  claim 4 , wherein determining the relationship further comprises calculating a current function, wherein the current function is a function of the temperature of air entering the evaporator fan, the target temperature of the evaporator fan, and the speed of the evaporator fan. 
     
     
       6. The method of  claim 1 , further comprising determining a first relationship between the current through the suction valve comprises and at least one of a temperature of air entering the evaporator fan, a target temperature of the evaporator fan, and a first evaporator fan speed; and
 determining a second relationship between current through the suction valve and at least one of the temperature of air entering the evaporator fan, the target temperature of the evaporator fan, and a second evaporator fan speed. 
 
     
     
       7. The method of  claim 6 , wherein determining the first relationship comprises calculating a first current function I 1 , wherein the first current function I 1  is a function of the temperature of air entering the evaporator fan, the target temperature of the evaporator fan, and the first evaporator fan speed, and wherein determining the second relationship comprises calculating a second current function I 2 , wherein the second current function I 2  is a function of the temperature of air entering the evaporator fan, the target temperature of the evaporator fan, and the second evaporator fan speed. 
     
     
       8. The method of  claim 7 , further comprising calculating a third current function I 3 , the third current function I 3  being a function of at least one of the first and second current functions I 1 , I 2  to determine the current through the suction valve. 
     
     
       9. The method of  claim 8 , wherein the third current function I 3  is a function of the fan speed (vfan) of the evaporator fan. 
     
     
       10. The method of  claim 9 , wherein determining the current through the suction valve comprises inputting a given fan speed into the third current function I 3 , and wherein the determined current is equal to a value of the third current function I 3  at the given fan speed. 
     
     
       11. The method of  claim 10 , further comprising setting the current through the suction valve equal to the value of the third current function I 3  at the given fan speed. 
     
     
       12. The method of any of  claims 8 - 11 , wherein the third current function I 3  is given by the formula:
     I 3=(1− x ) I 1+ xI 2,
 
 
       wherein x is a function of the fan speed of the evaporator fan:
     x=fx ( v fan). 
 
     
     
       13. The method of  claim 12 , wherein the first evaporator fan speed is a minimum fan speed and wherein the second evaporator fan speed is a maximum fan speed. 
     
     
       14. The method of  claim 13 , wherein fx=0 for a minimum fan speed and wherein fx=1 for a maximum fan speed. 
     
     
       15. A vehicle air conditioning system comprising:
 a compressor configured to compress refrigerant, the compressor comprising a compressor suction valve configured to draw refrigerant into the compressor; and 
 an evaporator comprising at least one coil and an evaporator fan configured to direct air entering the evaporator toward the at least one coil; 
 wherein the system is configured to direct compressed refrigerant from the compressor toward and through the at least one coil of the evaporator, and wherein the system further comprises:
 a controller with computer-readable instructions stored on memory thereof that when executed enable the controller to set a current through the compressor suction valve based on at least a speed of the evaporator fan. 
 
 
     
     
       16. The vehicle air conditioning system of  claim 15 , wherein the speed of the evaporator fan is based on a desired interior cabin temperature, a temperature of air entering the evaporator fan, and a target temperature of the evaporator fan. 
     
     
       17. A system, comprising:
 an air conditioning system comprising a suction valve and an evaporator fan; and 
 a controller with computer-readable instructions stored on memory thereof that when executed enable the controller to:
 determine a first relationship between current through the suction valve and at least one of a temperature of air entering the evaporator fan, a target temperature of the evaporator fan, and a first evaporator fan speed; 
 determine a second relationship between current through the suction valve and at least one of the temperature of air entering the evaporator fan, the target temperature of the evaporator fan, and a second evaporator fan speed; 
 set a suction valve current based on an interpolation between the first relationship and the second relationship. 
 
 
     
     
       18. The system of  claim 17 , wherein the first evaporator fan speed is a minimum speed and the second evaporator fan speed is a maximum speed. 
     
     
       19. The system of  claim 17 , wherein the temperature of air entering the evaporator fan is based on an ambient air temperature within a vehicle cabin or outside of a vehicle cabin. 
     
     
       20. The system of  claim 17 , wherein the target temperature of the evaporator fan is based on a desired interior cabin temperature.